1. Field of the Invention
The present invention relates to a protractor designed to be used to measure and draw angles.
2. Description of the Prior Art
In U.S. Pat. No. 1,062,740 (Sharpe) there is disclosed a pocket protractor intended to occupy a minimum space. An outer ring member carries degree graduations and an intermediate ring member has a line marked to align with the graduations. The intermediate ring member rotates inside a circular aperture inside the outer ring member. A diametric crossbar is secured across the intermediate ring member and bears a bevelled side edge provided with graduations.
In German patent specification No. 53887 (Dumur) a semi-circular angular measuring device has an arm rotatable around a semi-circular scale, and has graduations marked on the arm.